Vicky, Camilla.

H1:SQZ-SHG_PZT_VOLTS is going from 55V to zero over ~40 hours, plot attached. In alog 68568 Vicky notes that when SHG PZT ran out of range, SQZ_MANAGER handles it fine, taking SQZ out of the IFO, relocking everything before re-injecting SQZ.  But to minimize this happening during long locks we've added a checker in LOCK_SHG and SQZ_READY_IFO to check if H1:SQZ-SHG_PZT_VOLTS < 15, return LOCK_SHG and take the SQZ_SHG guardian to DOWN back to LOCKED, which puts the PZT voltage in the middle of it's range.